Fleck 6700XTR cycles seem incorrect

My 6700 doesn't seem to be going through the cycles correctly. I just ran it through its cycles by manually starting a regeneration, the purpose being to measure the BLFC flow rate. I have it Regenerant Flow set to Down Flow Double Back Wash, which has 5 cycles:

First off, is your 6700XTR a single or double backwash valve? The valve is basically the same, the micro-switch cam would be different for single or double backwash. It is pretty easy to determine. Program the valve for single backwash, if the cycles match, then you have a single backwash valve. Same goes for the double backwash, program it to DBW, if the cycles match the programming you are good to go. One of them will not match.

So that was the issue. Looking carefully at the parts diagram I now see that there is a double backwash version of the cam. I'm not sure I understand why that would be necessary with a digital controller. It seems to me that the controller would be able to position the valve as needed for single or double backwash.

So that was the issue. Looking carefully at the parts diagram I now see that there is a double backwash version of the cam. I'm not sure I understand why that would be necessary with a digital controller. It seems to me that the controller would be able to position the valve as needed for single or double backwash.

What does double backwash provide? Is it worth changing over to?

Thanks,

Chris

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Double backwash is advantageous for ultra low salting, downflow brine applications. It is a simple way to eliminate the majority of the problems associated with ultra low salting. If you use 6 pounds or more per cu. ft. then it is not necessary. Even at 4 pounds per cu. ft., most people cant tell the difference.

The newer valves use optical sensors to determine where they are, the older valves, like the 5600SXT, 6700XTR, 2510 SXT, etc use physical micro switches. The double backwash cam has an extra spot in it for the micro-switches to position the valve in the second backwash position.

In my own testing, in a normal household application, it is difficult to tell the difference. Even with hardness ppm testers, (not GPG) unless the system is being run to the point of having virtually no reserve, it would be hard to notice any change between the two. When a system is pushed on flow and capacity, the double backwash does show a testable difference in water quality, ie: lower hardness bleed, but most people would not notice the difference.